Method of filtering cyanide slimes and apparatus for use in same



Jan. 21, w30. c, ,Lm-TECUM 1,744,480; METHOD OF FILTERING CYANIDE1SLIMES AND APPARATUS FOR USE IN SAME F1144 sept. 3, 1924 :s Sheets-Sheet 1 BY I u ATTOR EYS,

Jan. 2l, 1930. c. LINTECUM 1,744,480

METHOD OF FILTERING QYANIDE SLIMES AND APPARATUS FOR USE 1N SAME Filed Sept. 5, 1924 s sneetsfneet 2 v lNyf-:NTOR

T l* y l l i W Z6 56 9 5 24 l mm YS.

Jan. 2l, 1930. y c. LINTECUM 1,744,480 lMETHOD OF FILTERING CYANIDE SLINS AND APPARATUS FOR USE IN' SNE.

Filled Sept. 3. 1924 5 SheetsrSheet 3 INVENTOR Bw ATroRNE S,

Patented Jan. 21, 1930 UNITED STATES PATENT OFFICE CHARLES LINTECUM, OF TONOPAH, NEVADA METHOD OF FILTERING CYANIDE SLIIVIES AND APPARATUS FOR USE IN SAME Application filed September 3, 1924.

My invention relates to the method or process of filtering pulp and has for its object an elimination of excess pulp and Wash solution tanks together With a reduction of the amount 5 oi pumping required and a saving of time in transferring the pulp and Wash solutions.

It also relates to the apparatus employed in my method.

Another object is to secure a more conl tinuous and uninterrupted filtering action and to produce a minimum of accumulations of values in the Wash due to diffusion. In operating a stationary leaf pumping type ot' filter, the present practice is to pump the pulp into the filter, to form a cake, then to pump out the pulp, then to pump in the Washingsolution and to Wash the cake, then to pump out the solution and then to pump in Water and then to Wash, drop and discharge the cake.

In my improved method of filtration I use a plurality of filter compartments or vats of equal size, placed on the same level and operated in definite cyclic relation With one another, transferring the pulp and the Wash solutions from compartment to compartment instead of from the filter to excess tanks and back again.

Referring to the accompanying drawings 30 Fig. 1 shows a series of filters adapted to carry out my improved method, the same being a side elevation. Fig. 2 is a plan view of the same. Fig. 3 represents an elevation of' a preferred type of decanting device. Fig. 4 is a sectional view on the line 4 4 of Fig. 8. F o is a partial sectionshowing an alternative type of decanting device with a special form of inlet valve. Fig. 6 is a partial sectional. vievv of the filter showing one form of apparatus for operating the discharge gate at the bottom of the hopper. Fig. 7 is a partial plan vien7 showing the discharge gate at the bottom oit the filter compartment. Fig. S is a longitudinal section of an improved quick r closing type of valve. Fig. 9 is a cross section of the same. Fig. 10 is a horizontal section through the decanter shown in Fig. 5

and on the sectional line -10. Fig. 11 is an enlarged view, partly in section` of compartment C4 and tank 1A, showing the pipe con- Serial No. 735,634.

nections between these parts and the pump 3.

C-1, C-2, @-3, @-4, C-5, CMG and 0 7 represent filtering compartments Which may be of any desired size, form, construction or number. They should be on the same level systematically located With reference to the pump. 3 is the pump Which is used for pumping the pulp and the Wash solution from compartment to compartment and the Water to and from the excess tank l-A. 1-A is an excess tank for holding Water which is to be used in the Washing operation. Q-A is the pipe leading from the excess tank to the filtering compartment through which the Water may be fed from the tank to the filteringcompartments by gravity. 4 is a lter leaf of'any desired construction. 5 is a hose connection extending to the filter leaves and 6 is a header pipe, one of which is provided for each compartment of the filter. 7 is a discharge gate which is placed at the bottom ot the filter compartment, and which can be opened and closed by moving it horizontally in the guides 8. See Fig. 6. 9 is a seat on which the gate 'l' 1s closed. It may be of Wood or it may be a gasket of rubber or other desired form of packing. 3-A is an intake pipe extending Yfrom-the filter compartments to the pump 3 and 4-A is a discharge pipe extending from the pump to the filter compartments.

In Fig. 3 I have shown a preferred form of decanting device. 10 is a pipe of sheet iron shown in section in Fig. 4. It is hinged at 18 to pipe line 3A or 1 -A Which leads to the pump 3. 11 is a saddle or bonnet which encloses the pipe 10 and is hinged at 12 to the pipe 3A. or l-A. This saddle is for the purpose of preventing solids from entering through the flexible joint between the pipe 10 and the pipe 3A or 4-A. 14 is a cable or rope Which is connected With the pipe 10 by means of Which the pipe 10 can be raised to the position 10 as shovvn in dotted lines in Fig. 3. 15 marks baille plates in the end of the pipe 10, the purpose of which is to prevent cake from entering the pipe. The bottom of the pipe may he provided With holes if desired to facilitate the decanting.

In Fig. 5 I have shown an alternative type of decanter and also a special form of inlet valve. 15a is a pipe resting against the side of the filter compartment and connected at its bottom with a pipe leading to pump It is provided with battle plates 151 to prevent the cake from passing into the pipe. 17 is a gate at the bottom of the pipe 15a through which the final solution is decanted. 1G represents diagrammatically a rod or handle connected with the gate by means of which it is opened or closed. 18 is an iron door which is hinged at 21 to the wall of the hopper at the bottom of the filtering compartment. 19 is a gasket made of rubber or other suitable material upon which the gate 18 rests. 20 is a rod connected with the gate 18 and leading to a handle or toggle at the top of the compartment.

In Fig. (i which is partly in elevation and partly in section I have shown the discharge gates and apparatus for operating the same.

22 is a frame surrounding the lower end of the hopper to which the link 23 is pivoted. This link extends downwardly and its lower end is pivoted to a locking lever 241, the other end of which is pivoted at 28 to a rod 27. The rod 27 passes through a tube 29 the lower end of which rests on the frame 22 so that the tube is stationary. 30 and 31 are toggle levers pivoted together at The lowei` end of toggle lever 30 is pivoted at 33 to the tube 29. The upper end of toggle 31 is pivoted to a sleeve 31, encircling the rod 27. 34 is a wheel screwing on to the upper end oi' rod 27, and adapted to bear against the upper end of the sleeve 31L and thus to support the rod 27. 31b is a handle connected with the lower end of the toggle lcver 31. To lower the rod 27, the wheel 34 is slightly released, and the handle 31J is raised to the position shown in dotted lines moving the toggles to the position shown in dotted lines and thus dropping the wheel 34 and the rod 27. This relieves the pressure on the gate 7. 35 is a pivoted lever connected at its lower end with the rod 36 which is connected with the gate 7 at its inner end. Then the lever 24 has been moved to its lowermost position the upper end of the lever 35 is moved inwardly and the gate 7 is opened so that the cake may be discharged. 25 is a lug projecting down from the gate 7 against which the bar 24 is adapted to bear when in its uppermost position, thus holding the gate 7 tightly closed. 38, Fig. 6, is a deeanter, one of which is provided for each compartment for the purpose of removing a part of the more enriched wash solution from the top, resulting from diffusion. It may likewise be used for decanting solution from the top of compartments of pulp.

In Fig. 8 I have shown a longitudinal section of an improved quick closing type of Bunsen valve. Fig. 9 shows a cross section of the same. This valve is used on the pipe line which connects the filter compartments with the pump 3. 39 is a short section of flexible hose inserted in and clamped to the pipe line which runs from the compartment to the pump. lO-et() represent clamps of any suitable material which extend on opposite sides of the hose and which are pivoted at 10 to anj.Y suitable support. The outer end of the upper clamp is connected with a tube 41. The outer end of the lower clamp is connected with the rod Ll2 which extends upward through the tube. The upper ends ot the tube and rod are connected with any suitable device for operating them as, lor example, with a toggle arrangement such as shown in Fig. 6. lVhen it is desired to close this valve, the tube 4:1 is moved downwardly and the rod 42 is moved upwardly with equal and opposite movements thus compressing and flattening the tubular section and closing the valve as represented in broken lines in Figs. 8 and 9.

@ne lorin of my improved method would involve the use ot three filter con'ipartments, for example, @-1, @-2, and @-3. Let us assume that compartment @-1 is filled with slime pulp in which the caking operati n has just started and that a cake has been formed in compartment 2 and is being washed with wash solution which has just been pumped from compartment 3 to compartment @-2. later from the excess tank will be admitted to compartment @-3 and the cake in that compartment will be washed for twenty minutes and then will be dropped and discharged and the water will then be pumped back to the excess tank. Meanwhile the caking will have been completed in compartment @-1 and the solution washin g will have been completed in compartment @-2. The excess pulp Yfrom 1 is now pumped to 3 and the wash solution is pumped from @-2 to @-1. 'Vatcr will then be admitted from the tank A-l to compartn'ient C-2. During the next :forty minutes the caking operation will be carried on in compartment- @-3 and washing with a washing solution iill be carried on in con'ipartnient -1 and the cake will be washed in water and dropped in compartment 2. A more usual and preferred form of my i1ii] n'oved method for higher grade pulps, say pulp in which the solution contains around $5.00 per ton, would consist ol l or more coii'ipartments, for example @-1, 2, @-3 and @-1-..

Let us assume compartment 1 is filled with slime pulp in which the raking operation has just started and that a cake has been formed in conipartment @-2 and is being washed with solution which has just been pumped from compartment 3 to compartment @--2 and that a cake has been formed in compartment @-3 and is being washe'L with solution which has just been pumped llO from compartment @-4 to compartment @-3. later from l-A Will be admitted to compartment @-4 and the cake in that compartment Will be Washed for about 2O minutes and Will then be dropped, the Water being simultaneously decanted and returned to l-A, the cake is then discharged.

Meanwhile the caking Will have been com pleted in conipartinent @-1 and the excess pulp is noiv pumped to compartment @--l and the Wash solution in compartment @-2 is pumped to compartment @-1 and the Wash solution in compartment @-3 is pumped to compartment @-2. Water will then be admitted from l-A to compartment @-8, the cake in that compartment Washed about 2O minutes, then dropped while the Water is being decanted and returned to l-A. Discharge door 7 is now opened and the cake' discharged.

In thc next cycle the caking Will take place in compartment @-3 While the cake just formed in compartment @-t is Washed with solution from compartment @-l and the cake in compartment @-1 is Washed with solution 'from compartment @--2 and the cake in compartment @-2 is given a Water wash ot about 2O minutes, then dropped While the Water is being decanted and returned to l-A. The cake is then discharged.

In another and more complete form' of' my improved method I employ seven or more compartments as shown in Fig. l.

Let us assume that compartments @-1 and @-2` have just been filled with pulp so that the cakingl operation is proceeding in those compartments, the operation in compartment @-2 being ahead oit the operation in compartment @-1 by substantially halt the (raking period. In compartments @-3 and @-4 the Washing` operation with a lirst Wash Will be proceeding, the operation in @-ll being-ahead of the operation in @-3 by halll the caking period. In compartments @-5 and @-6 the Washing With the second Wash will be proceeding, the operation in @-6 being ahead of the operation in @-5 by hall the caking period. Water has been pumped or flowed into compartment @-7 trom the excess tank l-A and the Washing has been proceeding for halt the caking period. In @--7 the cake is then dropped. Vvlhiie the cake is being dropped in @-7 the Water in which it is being dropped will be dccanted through the decanter shown in Fig. 3 0r shown in Fig. 5 into the pipe leading to the pump 3 and pumped to the tank 1--A. The cake having been dropped from the leaves and the water decanted in @-7, the discharge gate 7 is opened and the cake discharged from that compartment. The pulp is then pumped from @-2 to @-7 with additional pulp 'from the pulp tank. Wash from @-4: is pumped to @-2 and Wash from @-6 is pumped to @-4. TWater is then pumped or flowed from excess tank l-A to @-6 and short Water Wash given. rThe cake on the leaves @-6 is now dropped and discharged at the same time that the excess Water is decanted and pumped back to the excess tank. This completes the first phase ot the cycle.

Pulp from @-l is new pumped to @-6, Wash from @-3 to @-1 and Wash from @-5 t0 @-3. The Water is then admitted from the tank l-A to @-5 and short Water Wash given. rllhe cake is then dropped and discharged in @-5 the excess water having` been returned to l-A While the cake was dropping. This completes another cycle. In like manner in the nent cycle the pulp is transferred trom @-7 to @-5 and the Wash is transferred from @-2 to @-7 and so on in continuous cycles.

It will be seen from this description that in my improved method there is aminimum of pumping,` required as the pulp and the Washing solution are not pumped back and forth between the filtering compartments and excess tanks but are pumped from compartment to compartment. All of the charges ci pulp and of Washing solutions are passed through all seven compartments in succession. To minimize the accumulation of values in the Washes due to diffusion the Wash solution in this form oil lilter may be advanced in series instead ot being advanced in parallel as indicated, i. e. When the pulp is pumped from compartment @-2 to compartment the Wash solution in compartment @-3 will be pumped to @-2, that in @-e Will be pumped to @-3, that in @-5 Will be pumped t0 @-/l and that in @-6 Will be pumped to @-5. Water from 'l-A Will then be admitted to compartment @-6, the cake Water washed for the time available, the cake dropped, the Water meanwhile being returned to l-l-i and the cake discharged.

In this form and likewise in those previously described this accumulation or values in the Washes may be minimized by the use of the decanter shown in 38, Fig. 6. rllhe most enriched Wash solution, being1 in the compartment in which. the cake has been most recently formed, is decanted to precipitation While Washes in succeeding); compartments are decanted and advanced in order, thus the compartment Which has been Washing longest and contains practically barren solution, may receive barren solution in amount equal to that decanted plus that Which is drawn into the cake in all ot the compartments that are Washing.

In certain cases, it may be preferable to operate by transferring, instead of the water Wash as heretofore described, a compartment of pulp or solution to the excess tank to permit of the transfers being` made, or, the eftcess tank l-A may be replaced by an additional filtering compartment to advantage when the caking period is relatively short and the time of transfers relatively long.

The operation of a four-compartment filter, transferring the first solution Wash to the excess tank, would be as follows:

Assume that compartment C-l is filled with slilne pulp in which the caking operation has ust started and that a. cake has been formed in compartment @-2 and is being Washed with the first wash solution admitted from l-A; that the cake in compartment @-3 is being Washed with a second Wash solution previously used on the cake in compartment @-4 and that the cake in compartment 4 is being washed with the third wash, mostly water containing a small amount of cyanide, decanted from compartment 1 while the cake was being dropped Yfor discharge. lVhcn the Washing in @-2 has continued for a time equal to the caking period less the time required to transfer all comjmrt ments and discharge the cake in the final compartment, or about minutes, the wash is returned to l-A whence it came. lash from @-3 is then transferred to @-2 a ,d the Wash in C-4 is decanted and transferred to @-3 While the cake in Jt is being.;` dropped for discharge.

`When the cake has been discharged from compartment @-4, it is filled With pulp from C-l with additional pulp from the stock tank and the first wash is admitted 4from l-A.. to compartment @-1. Vhen this Wash has been on about 20 minutes, it is rcturnctV to l-A and replaced by Wash No. 2 from compartment 2 and the filial Wash is decanted and transferred from compartment 3 to compartment @-2 While the cake is being dropped in compartment @-3. lVhen the cake has been discharged from compartment C-B. it is filled With pulp from @-4 with additional pulp from the stock tank. In like manner, a filter of three, five or more compartments would be operated.

The operation of a four-compartment filter without the use of excess tank l-A would be as follows:

Assume that compartment 1 is filled With slime pulp in which the caking operation has just started and that a cake has been formed in compartment @-2 and is being Washed with the first Wash solution previously used on the cake in C-S and that the cake in compartment @-3 is being Washed with the second or final Wash, mostly Water containing a. small amount of cyanide, decanted from compartment @-4 while the cake was heilig dropped for discharge.

When the cake has been formed in compartment C-l, the pulp With additional pulp from the stock tank is pumped to @-4-, the first wash in 2 is pumped to @-1 and the second wash in @-3 is pumped to @-2 as decanted from the cake being dropped in C-3. The dropped cake in @-3 is then discharged.

When the cake has been formed in compartment 4, the pulp With additional pulp from the stock tank is pumped to @-3, the first wash in compartment 1 is pumped to C-t and the second wash in compartment C-2 is pumped to @-l as decanted from the cake being dropped in compartment @-2. The dropped cake in @-2 is then discharged.

In like manner, a. filter of three, five or more compartments would be operated.

Another Way of carrying out my improved method would be as follows. Assuming minutes for the caking period and 312 minutes :for the transfer between the compartments, let us consider that in compartment 1 the caking operation has continued for l() minutes, that in @-2 the caking operation has continued for 2O minutes, that in 3 it has continued for 30 minutes, iha in (l-l it continued for 40 minutes, that in the washing operation has been going on for 10 minutes with Wash Water prexiously used G and. that in C-G the Wash operation has been going on 'for 2O minutes with Water transferred from @-7 and that in 7 the cake has been dropped so that @-7 is ready for a new charge. The pulp in i is now pumped to @-7 and the Wash in C- is pumped to 4. The `Wash from 6 is pumped into 5. Meanwhile the cake has been dropped in @-6 so that @-G is now ready for a new charge, The caking has now continued for a() minutes in after which the excess pulp is pumped into 6 together with additional pulp from the stock tank.- The wash from @-4 is now pumped into @-3. rlhe cake having been dropped in C--the wash from C- is pumped into @-4l^. Then the caking opera.- tion has proceeded for i0 minutes in @-2 the pulp is pumped from @-2 into @-5.A The wash is pumped :from 3 into @-.i. rfhe cake hai-Jing been dropped in fl-the Wash is pumped from @-4 into 3.

As soon as the caking has proceeded 410 minutes in @-1 the pulp is pumped from @-1 to @-4. The first wash is pumped from @-2 into C-l. The `cake having been dropped in @-3-tlie second Wash is pumped from @-3 into 2. In like manner the cycle of operation is continued, the pulp passing from the compartment Where the torniation of the cake has just been completed to the compartment Where the cake has just been dropped and the wash Watr passing from compartment to compartment in proper sequence.

lhen operating in this manner the hoppers are kept full of discharged cake nearly up to the bottom of the leaves. Then the cake is being dropped the discharge door 7 is opened and sufiicient cake let out to make room for that being dropped, so that substantially the cake from each cycle remains in the hopper till the next cycle. In the operation of my lter it will be necessary to provide one or more suction lines from the filter headers to a tank or tanks below for the purpose or holding` the cake on the filters in case of the power going off. Gr an auxiliary source of dependable power may be provided to maintain vacuum in this event.

One of the important and valuable teatures ot' my invention consists in the employment of one more compartment than the number of caking and washing operations to be simultaneously performed or of an excess tank in place ofsaid extra compartment.

Vhat I claim and desire to secure by Letters Patent is:

l. The method of iiltering slimes which consists in sin'iultaneously operating a plurality ot lilter compartments in a continuous cycle, by forming a cake in one compartment, washing a cake with wash solution in a second compartment, washing a cake with water in a third compartment, then dropping and discharging the cake in the third compartment, pumping the water out ot the third compartment into an excess tank, pumping the slime pulp from the first compartment to the third compartment, pumping the wash solution from the second compartment to the first, supplying water from the excess tank to the second compartment, then washing, dropping and discharging the cake in the second compartment while the cake is torming in the third compartment, and the cake is being washed with wash solution in the lirst compartment, substantially as described.

2. The method of filtering slimes which consists in simultaneously operating a plurality ot lilter compartments in a continuous cycle, by forming a cake in one compartment, washing a cake with waterin another compartment, washing a cake with wash solution in a third compartment, then dropping` and discharging the cake that has just been Washed with water, pumping the water back to the excess tank, then pumping the pulp slimes trom the compartment where the cake has been 'formed to the compartment `from which the water has just been pumped, pump ing the wash solution into the compartment 'from which the slimes have been pumped, and supplying water from the excess tank to the compartment vfrom which the wash solution has been pumped, then dropping and discharging the cake in the last mentioned compartment.

3. rl`he method of filtering slimes which consists in simultaneously operating a series of iilter compartments, forming a cake in one or more of such compartments, simultaneously washing a cake with wash solution in one or more compartments, and simultanea ously washing, dropping and discharging a cake in one or more compartments, pumping the slimes, and wash solution from compartment to compartment in proper sequence, and pumping the wash water, after being used, back to the excess tank, and then supplying it to the compartment or compartments in which the cake is to be dropped next, substantially as described.

e'. The method of filtering slimes which consists in simultaneously operating a series ot lilter compartments, forming a cake in one compartment, washing, dropping and discharging the cake in another compartment, simultaneously Washing the cake with wash solution in a series of two or more compartments in diti'erent stages of advancement of the washing operation, pumping water from the compartment where the cake is being dropped to an excess tank, pumping the slimes from the compartment where the cake has just been formed into the compartment where the cake has just been dropped, pumping the wash solution from compartment to compartment in proper sequence, supplying water from the excess water tank to the compartment where the washing with wash solution has just been completed and supplying additional slimes, wash solution and wash water to the respective compartments, substantially as described.

5. In an apparatus 'or filtering slimes the combination of a series ot filter compartments, a pump, a series ot pipes connecting the dirlerent compartments and the pump so that the contents of the compartments can be pumped from compartment to compartment in proper sequence, an excess water tank, pipes connecting the excess tank with the several compartments and with the pump wher by, after the cake has been washed and dropped in any compartment, the water can be pumped to the excess tank and whereby, atter the cake in any compartment has been washed with wash solution, water can be supplied from the excess tank to that compartment all substantially as described.

6. The method of iiltering slimes which consists in simultaneously operating a plu rality of filter compartments in a continuous cycle by filtering the pulp in one compartment so asrto form a cake, at the same time washing the cake previously formed in a number of compartments, dropping the cake in another compartment, advancing the pulp -from compartment to compartment, leaving it in each compartment a sutticient length of time to form a cake therein, advancing the washing liquid from compartment to compartment following the pulp, pumping the washing liquid from a compartment after the cake has been dropped therein to an extra tank, and then advancing the pulp to that compartment, and pumping the liquid from the extra tank to the' compartment that has been left empty, and repeating this operation whenever a cake has been completely formed in any compartment, substantially as dc scribed.

7. The method of filtering sliines which consists in simultaneously operating a plurality of filter compartments in a continuous cycle, by forming a cake in one or more compartments, washing the cake with wash solution in one or more compartments, washing the cake with water in another compartment, supplying this water from a water tank, dropping the cake in that compartment after it has been washed with water, then pumping the water back to the tank, pumping the slimes from a compartment in which a cake has been formed to the compartment Where the cake has just been dropped, pumping the wash solution from compartment to compartment immediately following the slimes, thus leaving a compartment empty With a cake ready to be washed with water,r pumping water from the water tank to said compartment, washing the cake therein with the Water, then pumping the v:iter back to the water tank and dropping the cake an( repeating these operations successively in said compartments substantially as described.

8. The method of filtering slimes which consists in simultaneously operating a plurality of filter compartments in a continuous cycle, which consists in providin an extra, tank or compartment, filtering the pulp in one or more compartments, washing the cake in other compartments with wash solution or water, dropping the cake in one of the coinpartments when it has been sufficiently washed and, while this cake is being dropped, pumping one of the liquids from one of the compartments to the extra tank leaving one compartment empty, transferring the liquids from compartment to compartment in proper order, thus leaving another compartment empty, then supplying the last named com partment with liquid from the extra tank and forming, Washing and dropping the cake in the respective compartments as before and repeating the operation in continuous cy cles, substantially as described.

9. The method of filtering slimes which consists in simultaneously operating a plurality of filter compartments in a continuous cycle by forming a cake in one or more compartments, at the same time washing a cake in one or more compartments, dropping and discharging the cake after it has been washed, transferring one of the liquids to an extra tank or compartment, then transferring the second liquid to the compartment or compartments from which the first liquid was transferred, then transferring the first liquid from the extra tank or compartment to the compartment or compartments from which the second liquid was transferred, then forming a cake as before in one or more con'ipartments and at the same time wi shing a cake in one or more compartments, dropping and discharging the cake after it has been wasned, and then continuing the above operation iintil the filtering of the sliines has been completed.

l0. In apparatus for filtering slimes, the combination of a plurality of filter cou'ipart'- ments, au excess liquid tank, a pump, pipes connecting each compartment with said pump whereby the contents of each coml'iartmen'.: may be passed therefrom to another of said compartments, and pipes connecting' said ef;- cess tank with said pump and with each coinpartnient whereby the contents of said tank can be transferred to any of said compartments and the contents of any compartment may be transferred to said tank.

l1. The method of filtering shines, by means of a plurality of compartments, which comprises forming a filter cake in one coinpart-uient. simiiitaiieoiisly washing that cake and forming a cake in another compartment, remoif'ingcii'ash liquid and washed cake from said first mentioned compartment, passing residual slime from said other compartment to a compartment from which a washed cake has been removed, washing the cake in said other compartment and repeating the cycle of operations.

ln testimony whereof, I have my name to this specification.

CHAS. LNTECUM.

ice 

